Rcd soft start circuit for dc-ups system power supply and power supply circuit thereof

Abstract

The utility model provides a kind of RCD slow start circuit and its power supply circuit for DC-UPS system power supply, the RCD slow start circuit is configured to be connected with the pin of power supply chip U9, it includes resistance R105, capacitor C45 and diode D12;Wherein, resistance R105 one end is connected with the LX pin of power supply chip U9, the other end connects capacitor C45, and the connecting line between resistance R105 and capacitor C45 connects the EN pin of power supply chip U9;Capacitor C45 other end connects the VCC and GND pin of power supply chip U9;The anode of diode D12 connects the connecting line between resistance R105 and capacitor C45, the cathode of diode D12 connects the LX pin of power supply chip U9;Resistance R105 is used to limit the charging current of the capacitor C45, capacitor C45 is used to control the rise time of the EN pin voltage of power supply chip U9, diode D12 is used to provide fast discharge path for capacitor C45 when DC-UPS system is powered off. It can effectively reduce the start-up current of DC-UPS system power supply, with the advantages of low cost, strong reliability, low circuit power consumption.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to an RCD soft-start circuit and its power supply circuit for a DC-UPS (DC uninterruptible power supply) system power supply. Background Technology

[0002] A DC-UPS (DC uninterrupted power supply) is a device that continuously supplies DC power when the mains power is interrupted. It is mainly used in power system upgrades, industrial automation control, and data centers. Currently, the power supply chip U9 in existing DC-UPS systems often exhibits excessive starting current during load startup. Especially during full-load startup, the input current increases sharply, causing the input voltage to drop, potentially damaging the power supply chip U9 or load devices, and triggering the system's overcurrent protection mechanism or battery management system (BMS) protection, leading to system malfunction or even failure. Existing technologies often use RC delay circuits to implement a soft-start function, which uses a combination of resistors and capacitors to slowly rise the voltage of the enable (EN) pin of the power supply chip U9 to limit the starting current. However, this solution has significant drawbacks. During rapid power-on / off switching, the capacitor discharges slowly and cannot be fully discharged in a short time, causing the soft-start function to fail on the next startup, resulting in a still large starting current, ineffective suppression of inrush current, and low system reliability.

[0003] Therefore, in view of the problems existing in the prior art, it is of great importance to provide an RCD soft-start circuit and its power supply circuit technology for DC-UPS system power supply that has high reliability, fast response speed and simple circuit structure. Utility Model Content

[0004] The purpose of this invention is to avoid the shortcomings of the prior art and provide an RCD soft-start circuit for DC-UPS system power supply and its DC-UPS system power supply circuit. By utilizing a soft-start circuit composed of three passive components (i.e., resistor R105, capacitor C45 and diode D12), the starting current of the DC-UPS system power supply is effectively reduced.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This utility model provides an RCD soft-start circuit for DC-UPS system power supply, wherein the RCD soft-start circuit is configured to be connected to the pins of power chip U9;

[0007] The RCD soft-start circuit includes a resistor R105, a capacitor C45, and a diode D12. One end of resistor R105 is connected to the LX pin of the power chip U9, and the other end is connected to capacitor C45. The connection line between resistor R105 and capacitor C45 is connected to the EN pin of the power chip U9. The other end of capacitor C45 is connected to the VCC and GND pins of the power chip U9. The anode of diode D12 is connected to the connection line between resistor R105 and capacitor C45, and the cathode of diode D12 is connected to the LX pin of the power chip U9.

[0008] The resistor R105 is used to limit the charging current of the capacitor C45, the capacitor C45 is used to control the rise time of the voltage on the EN pin of the power chip U9, and the diode D12 is used to provide a fast discharge path for the capacitor C45 when the DC-UPS system is shut down.

[0009] Specifically, addressing the issues of excessive current during startup in existing DC-UPS systems and the inability of traditional RC soft-start circuits to limit current during rapid power-on / off switching, the aforementioned technical solution utilizes a soft-start circuit composed of an RCD (resistor R105, capacitor C45, and diode D12). This circuit effectively limits the current during DC-UPS system startup and also provides current limiting during rapid power-on / off switching, reducing the risk of triggering protection. The RCD soft-start circuit operates as follows: upon power-on, the SVIN pin of the power chip slowly charges capacitor C45 through resistor R105, causing the voltage at the EN pin of the power chip to slowly rise to the chip's startup voltage. The DC-UPS system's power chip gradually increases its output based on the voltage at the EN pin, with the current slope determined by the time constant of resistor (R105) × capacitor (C45), resulting in a relatively low startup current for the DC-UPS system. When the power is off, the charge in capacitor C45 is rapidly discharged through diode D12, thus ensuring that the voltage of capacitor C45 returns to a relatively low voltage state before the next power-on. During rapid power-on and power-off, the soft-start circuit can start normally with current limiting.

[0010] The resistance value of resistor R105 and the capacitance value of capacitor C45 are determined by the startup voltage of power chip U9 and the required soft-start time constant.

[0011] The diode D12 mentioned above is a switching diode or a Schottky diode.

[0012] Preferably, the diode D12 is of model 1N4148WS.

[0013] This utility model also provides a DC-UPS system power supply circuit, including a power chip U9 and an RCD soft-start circuit for DC-UPS system power supply as described above, wherein the pins of the power chip U9 are connected to the RCD soft-start circuit.

[0014] Specifically, the aforementioned RCD soft-start circuit and power chip U9 are connected to form a DC-UPS system power circuit, which can suppress surge current.

[0015] The power chip U9 mentioned above includes LX pin, NC pin, EN pin, SVIN pin, VCC pin, GND pin, BS pin, MODE pin, ILMT pin, FS pin, FB pin, and OUT pin.

[0016] Preferably, there are multiple LX pins, NC pins, and OUT pins.

[0017] Preferably, the power chip U9 is model JP6513.

[0018] The above-mentioned OUT pin is connected to the DC power supply plug.

[0019] In addition, an inductor L6 is provided on the connection line between the LX pin of the power chip U9 and the resistor R105. One end of the inductor L6 is connected to the LX pin of the power chip U9, and the other end is connected to the resistor R105.

[0020] The beneficial effects of this utility model are:

[0021] This invention provides an RCD soft-start circuit and its power supply circuit for DC-UPS systems. The RCD soft-start circuit requires no software control and is formed by combining only three passive components (resistor R105, capacitor C45, and diode D12). It effectively reduces input current, prevents the DC-UPS system from triggering overcurrent protection, and ensures system stability. Furthermore, diode D12 provides a fast discharge path for the capacitor during power-off, supporting rapid power-on and power-off. Simultaneously, after adopting the RCD soft-start circuit in the DC-UPS power supply system's power supply circuit, the start-up current decreases significantly, and rapid power-on and power-off still allow for normal soft-start operation. It has advantages such as low cost, high reliability, and low power consumption. Attached Figure Description

[0022] Figure 1 A schematic diagram of the circuit structure of the RCD soft-start circuit provided in this embodiment of the utility model;

[0023] Figure 2 A schematic diagram of the circuit structure of the DC-UPS system power supply circuit provided in this embodiment of the utility model. Detailed Implementation

[0024] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, this embodiment provides an RCD soft-start circuit for a DC-UPS system power supply. The RCD soft-start circuit is configured to be connected to the pins of the power chip U9. The RCD soft-start circuit includes a resistor R105, a capacitor C45, and a diode D12. One end of the resistor R105 is connected to the LX pin of the power chip U9, and the other end is connected to the capacitor C45. The connection line between the resistor R105 and the capacitor C45 is connected to the EN pin of the power chip U9. The other end of the capacitor C45 is connected to the VCC and GND pins of the power chip U9. The anode of the diode D12 is connected to the connection line between the resistor R105 and the capacitor C45, and the cathode of the diode D12 is connected to the LX pin of the power chip U9. The resistor R105 is used to limit the charging current of the capacitor C45. The capacitor C45 is used to control the rise time of the voltage at the EN pin of the power chip U9. The diode D12 is used to provide a fast discharge path for the capacitor C45 when the DC-UPS system is shut down. The RCD soft-start circuit operates as follows: When power is applied, the SVIN pin of the power chip slowly charges capacitor C45 through resistor R105, and the voltage at the EN pin of the power chip slowly rises to the chip's startup voltage. The power chip of the DC-UPS system gradually increases its output based on the voltage at the EN pin, and its current slope is determined by the time constant of resistor (R105) × capacitor (C45). The startup current of the DC-UPS power system is relatively small. When power is off, the charge in capacitor C45 is rapidly discharged through diode D12, thereby ensuring that the voltage of capacitor C45 returns to a relatively low voltage state before the next power-on. During rapid power-on and power-off, the soft-start circuit can start normally with current limiting. In this embodiment, the diode D12 is model 1N4148WS.

[0026] like Figure 2 As shown, this embodiment also provides a DC-UPS system power supply circuit, including a power chip U9 and an RCD soft-start circuit for DC-UPS system power supply as described above. The pins of the power chip U9 are connected to the RCD soft-start circuit, which can suppress surge current.

[0027] In this embodiment, the power chip U9 is model JP6513. The power chip U9 includes three LX pins, three NC pins, an EN pin, an SVIN pin, a VCC pin, two GND pins, a BS pin, a MODE pin, an ILMT pin, a FS pin, an FB pin, and four OUT pins. The four OUT pins are connected together, and the leads are connected to the DC power supply's plug.

[0028] After the three LX pins of the power chip U9 are connected together, they are connected to one end of the inductor L6; the other end of the inductor L6 is connected to the resistor R105, the other end of the resistor R105 is connected to the capacitor C45 and the EN pin of the power chip U9; the diode D12 is connected in parallel on both sides of the resistor R105; one end of the capacitor C45 is connected to the resistor R105 and the EN pin of the power chip U9, and the other end is connected to the VCC and GND pins of the power chip U9.

[0029] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. An RCD soft-start circuit for DC-UPS system power supplies, characterized in that, The RCD soft-start circuit is configured to be connected to the pins of the power chip U9; The RCD soft-start circuit includes a resistor R105, a capacitor C45, and a diode D12. One end of resistor R105 is connected to the LX pin of the power chip U9, and the other end is connected to capacitor C45. The connection line between resistor R105 and capacitor C45 is connected to the EN pin of the power chip U9. The other end of capacitor C45 is connected to the VCC and GND pins of the power chip U9. The anode of diode D12 is connected to the connection line between resistor R105 and capacitor C45, and the cathode of diode D12 is connected to the LX pin of the power chip U9. The resistor R105 is used to limit the charging current of the capacitor C45, the capacitor C45 is used to control the rise time of the voltage on the EN pin of the power chip U9, and the diode D12 is used to provide a fast discharge path for the capacitor C45 when the DC-UPS system is shut down.

2. The RCD soft-start circuit according to claim 1, characterized in that, The resistance value of resistor R105 and the capacitance value of capacitor C45 are determined by the startup voltage of power chip U9 and the required soft-start time constant.

3. The RCD soft-start circuit according to claim 1, characterized in that, The diode D12 is a switching diode or a Schottky diode.

4. The RCD soft-start circuit according to claim 3, characterized in that, The diode D12 is model number 1N4148WS.

5. A DC-UPS system power supply circuit, characterized in that, It includes a power chip U9 and an RCD soft-start circuit as described in any one of claims 1-4, wherein the pins of the power chip U9 are connected to the RCD soft-start circuit.

6. The DC-UPS system power supply circuit according to claim 5, characterized in that, The power chip U9 includes LX pin, NC pin, EN pin, SVIN pin, VCC pin, GND pin, BS pin, MODE pin, ILMT pin, FS pin, FB pin, and OUT pin.

7. The DC-UPS system power supply circuit according to claim 6, characterized in that, The LX pin, NC pin, and OUT pin have multiple pins.

8. The DC-UPS system power supply circuit according to claim 6, characterized in that, The power chip U9 is model number JP6513.

9. The DC-UPS system power supply circuit according to claim 6, characterized in that, The OUT pin is connected to the DC power supply plug.

10. The DC-UPS system power supply circuit according to claim 6, characterized in that, An inductor L6 is also provided on the connection line between the LX pin of the power chip U9 and the resistor R105. One end of the inductor L6 is connected to the LX pin of the power chip U9, and the other end is connected to the resistor R105.

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